In Canadian patent application Ser. No. 395,013 filed Jan. 27, 1982, now Canadian Pat. No. 1,165,474 there is described a process for removal of cyanide from aqueous effluent solutions which comprises reacting the cyanide with sulfur dioxide (or its equivalent as an alkali or alkaline earth sulfite, bisulfite or pyrosulfite) and oxygen in the presence of soluble copper at a pH in the range of about 4 to 12. On occasion cyanide-containing effluent solutions from gold mine operations also contain arsenic or antimony which should be removed in order to provide treated effluent solution which can be discharged with minimal damage to the local environment.